Local network excitation is higher and less effectively controlled by GABA B Rs in VH compared with DH Spontaneous field potentials (spfps) induced under conditions of blockade of GABA A Rs (Fig. 1b) were comparatively studied in DH and VH slices (Fig. 1c). GABA A R-mediated transmission was reduced by applying different concentrations of the antagonist of GABA A R SR 95531, from 0.1 to 10 μM. The incidence of spfps in the slice population (i.e. the percentage of slices displaying spfps) and the rate of spfps in each drug concentration were measured in DH and VH. Perfusing slices with increasing concentrations of SR 95531 induced the appearance of spfps in a, respectively, increasing number of slices, in both DH and VH. Furthermore, the incidence of spfps was very different between DH…